INCREASE THE VALUE OF YOUR POWER PLANT: Power Augmentation Technologies for Existing Simple-Cycle and Combined-Cycle Power Plants

摘要

One of the most economically attractive ways to increase the value of an existing power plant is to invest in capital improvements that will increase profit margins during high demand periods and higher electricity prices. Power augmentation technologies offer the flexibility to quickly provide additional power during these peak periods, and to quickly return to normal operation when they no longer provide economic benefit. Evaporative cooling of the inlet air of a combustion turbine (CT), using media-type coolers or inlet foggers, is one of the more popular methods of power augmentation, mostly for its relative ease of implementation, low incremental capital and O&M costs, and modest power gains during times of high ambient temperature (normally coincident with high-demand periods). Inlet chilling similarly cools the air entering the CT; however, it uses indirect contact with chilled liquid through a series of coils located in the CT inlet ducting, eliminating the chance of water carryover into the compressor that is a concern with the evaporative cooling methods. Similar to evaporative cooling, wet compression uses evaporative cooling effects within the compressor to create an intercooling effect, substantially improving the efficiency of the compressor and increasing the net power output of the CT. Supplementary firing of a Heat Recovery Steam Generator (HRSG) can increase the output of a combined-cycle plant by as much as 25%, with relatively low incremental capital investment, if installed on a greenfield plant, or if it was considered in the original design of an existing plant. CT steam injection is yet another low-capital power augmentation technique, and CT peak firing can provide a quick power boost with virtually no capital expenditures and no required plant modifications. Figure 1 illustrates the effect of ambient temperature on power output with seven of the technologies addressed in this paper.